Cystic fibrosis is a disease that causes mucus in the body to become thick, dry, and sticky. This glue-like mucus builds up and causes problems in many of the body's organs, especially the lungs and pancreas. Cystic fibrosis is also known as mucoviscidosis, pulmonary fibrosis, and pancreatic cystic fibrosis. Approximately 30,000 people in the United States have cystic fibrosis. An additional 10 million more -- or about 1 in every 31 Americans -- are carriers of the defective gene, CFTR, but do not have the disease. The disease is most common in the white population but it can affect all races.